Overview
Browser extension for detecting and reducing CSS-based data exfiltration risk.
CSS Sentry is a local-only browser extension that helps detect and reduce risk from CSS-based data exfiltration techniques. It analyzes page styles for suspicious selector probing, remote CSS resource sinks, CSS imports, SVG/CSS resource behavior, data stylesheets, and rendered-content CSS injection patterns. The extension is designed as a defense-in-depth tool. It includes Passive, Balanced, and Strict protection modes, local reports, destination allow/block policy support, advanced compatibility options, and optional Firefox-specific enhanced stylesheet inspection. CSS Sentry does not use telemetry, cloud analysis, or a remote service. Reports are stored locally in your browser. This extension does not claim to prevent every CSS side channel, browser bug, sanitizer bypass, or future CSS feature. It is intended to reduce exposure to known high-signal CSS exfiltration patterns while minimizing normal browsing breakage.
Details
- Version1.0.86
- UpdatedMay 19, 2026
- Size263KiB
- LanguagesEnglish
- Developer
Email
dougg0k.apps@gmail.com - Non-traderThis developer has not identified itself as a trader. For consumers in the European Union, please note that consumer rights do not apply to contracts between you and this developer.
Privacy
This developer declares that your data is
- Not being sold to third parties, outside of the approved use cases
- Not being used or transferred for purposes that are unrelated to the item's core functionality
- Not being used or transferred to determine creditworthiness or for lending purposes
Support
For help with questions, suggestions, or problems, visit the developer's support site
